1. Field
Example embodiments relate to a method of manufacturing a reflective color filter, and more particularly, to a method of manufacturing a reflective color filter capable of reflecting light having a desired wavelength by controlling a lattice constant of a photonic crystal structure using a photonic crystal composite.
2. Description of the Related Art
By using ambient lights to brighten images on a screen, reflective displays have relatively high energy efficiency, relatively low power consumption, and relatively excellent legibility.
Photonic crystals have a lattice structure in which at least two materials with different refractive indices are regularly arranged two-dimensionally or three-dimensionally. Such a photonic crystal having the lattice structure has a photonic bandgap that may block or pass light with a certain wavelength due to periodic distribution of refractive indices.
For example, if the photonic bandgap of the photonic crystal is formed in a visible light region, and a frequency of light that is incident upon the photonic crystal corresponds to the photonic bandgap, theoretically, incident light is reflected by the photonic crystal by 99% or more. On the other hand, most of incident light having a frequency that is not within the photonic bandgap passes through the photonic crystal. Such three-dimensional reflective characteristics may be applied to a reflective color filter of a display. For this, R, G, and B pixels are required to have different photonic bandgaps.
The three-dimensional photonic crystals may be manufactured using a top-down method using lithography that is commonly used in the art and a self-assembly method using physical or chemical combinations of colloidal particles or polymers. The self-assembly (bottom-up) method is a relatively inexpensive and relatively easy process when compared with the top-down method. Vertical deposition by which colloidal particles are densely formed using evaporation of a solvent and a capillary force by vertically disposing a substrate, for example, glass in a colloidal solution having an appropriate particle size, natural gravity sedimentation, centrifugation, electrophoretic deposition, and solvent evaporation are generally used as the self-assembly method.
Theses methods still take a relatively long time and micro colloidal particles are relatively difficult to be controlled using them, and thus various processes are required to control the photonic bandgap of each region by patterning the photonic crystal structure. For example, each portion of the photonic crystals needs to be manufactured separately using colloidal particles having different sizes or reflective indices in order to control the photonic bandgap. In order to prepare different colloidal particles, templates need to be formed and removed each time. Repeatedly forming and removing templates may influence the previously formed crystal structure. Also, forming different photonic crystal structures using at least two colloidal particles by repeating the process is limited and relatively complicated.